Control of root-knot nematode (Meloidogyne spp.) on tomatoes by organic, chemical and by plant resistance techniques

Abstract

Techniques for controlling root-knot nematode (Meloidogyne spp.) in tomato include the use of organic amendments, chemicals such as nematicides as well as using resistant tomato plants. It is essential to study control techniques so that a choice of controls can be identified which will be of benefit to the tomato farmer. In this study the three control techniques were studied in detail so that their effectiveness could be determined. Compost, being an organic amendment gave significant control over nematode larvae when the volume of compost in the soil mixture reached 40%. This amount of compost would be recommended for horticultural potting mixtures. The agent or entity within the compost could not be determined as being a bacterium. The use of nematicides in both pot and field trials gave different degrees of control. Fenamiphos (Nemacur) gave excellent control in both pot and field trials whilst aldicarb (Temik) only gave control in the pot trial. Oxamyl (Vydate) fared poorly in both the pot and field trials. Compost, when incorporated at quantities of 450m 3 per hectare in the field trial, did reduce root galling but this was still insignificant. The only nematicide which would be recommended for root-knot nematode control in field tomatoes would be fenamiphos (Nemacur). Resistant tomato cultivars offer excellent control on soils infested with root-knot nematodes. All three techniques which were tested, namely compost, nematicides and plant resistance were found to effect control over root-knot nematode infestation. The degree and mechanism of control differed for the three techniques but excellent control was determined within each technique. The only technique which would, however be recommended for small-scale tomato farmers would be the use of root-knot resistant tomato cul ti vars.